Another Lemmon Valley Serial Killer?

[Ausgirl]

Joseph Naso had a home in Lemmon Valley.

But there could have been another killer in the area. I found a whole bunch of murders with similarities in the area in the 70's and 80's:

http://www.washoesheriff.com/MP-COOK.pdf
http://www.washoesheriff.com/MP-SMITH.pdf
http://www.washoesheriff.com/MP-WOODWARD.pdf
http://www.washoesheriff.com/MP-CRUMMETT.pdf

others possibly linked:

cause of death undetermined:
http://www.washoesheriff.com/MP-ROBINSON.pdf
http://www.washoesheriff.com/MP-BROWN.pdf

cause of death gunshot wound:
http://www.washoesheriff.com/MP-SANTOS.pdf
http://www.washoesheriff.com/MP-HARBEKE.pdf
http://www.washoesheriff.com/MP-WHITLOCK.pdf
http://www.washoesheriff.com/MP-JANEDOE.pdf


I really thought Cindy Cook would have been investigated as a possible Naso victim, but I can't find any information that she has. Anyhow, there's a bunch of women, mostly teenaged girls there, all murdered in or around Lemmon Valley and in similar circumstances - and nobody's called 'serial killer'?


What criterion is needed before police consider two or more murders to definitely be linked?